At the present time, several types of membrane oxygenators are being produced for sale in the United States of America. Most of these are of the parallel plate type although at least one is in coil form. Predominately, the membrane used is silicone rubber or microporous. As available membrane oxygenators are more expensive than the conventional bubble type devices, for short term use, membrane oxygenators must be made available at a more competitive price.
An object of the present invention, therefore, is to provide a unit capable of forming the functions for which it is intended, for instance, the transfer of a gaseous component in one stream to or from a liquid component in another stream. Specifically, with respect to a blood oxygenator, the unit must add sufficient oxygen and remove sufficient carbon dioxide to maintain a normal physiological state of the blood flow requirement. Fluid dynamic requirements must be within the constraints of the patient. Priming volume of the device, and lines, operating pressures, and flow rates must be within safe limits for the patient. Trauma to the physiological system through its use must be minimal. As long-term support may be necessary, their requirements must be satisfied for extended periods of time, such as weeks.
Such a unit, as described herein, for blood oxygenation comprises a diffusion or microporous type membrane assembly comprising a continuous length of flattened tubular membrane and a gas net passing through the intermediate portion of the membrane from end to end thereof and substantially the width of the interior of the flattened membrane, this membrane assembly being wrapped firmly in layers around a rigid cylindrical core providing a coil, with a blood net separator between the membrane layers of the coil, and with an inlet tube for one of the components communicating with one end of the membrane and an outlet tube for the same component communicating with the other end of the membrane, together with means for causing the passing of another of the components longitudinally of the coil between the membrane layers from one end of the coil to the other end.
Other objects and advantages of this invention will be apparent from the accompanying description and drawings and the essential features thereof will be set forth in the appended claims.